1. Field of the Invention
The present invention relates to an apparatus for optically measuring a fine area in an object to be measured with high spatial and time resolution.
2. Prior Art
Recently, the necessity of optically measuring a fine area in an object of measurement with high spatial and time resolution has increased in the fields of biophysics, life science, chemistry, biology and the like. For example, such necessity has occurred in the case of detecting a tumor cell mixed into normal cells by using the fluorescent phenomenon of HpD incorporated into the tumor cell or in the case of measuring the HpD distribution in a tumor cell. In those case, it is necessary to measure a fine area of the order of tens of .mu.m, so that the spatial resolution of the order of .mu.m and the time resolution of the order of ps are required.
For such measurement, a method using a microscope and a streak camera in combination may be proposed. However, the method has problems as follows.
(1) When the microscope and the streak camera are combined, the optically adjusting or slightly adjusting mechanism becomes complicated.
(2) It is difficult to integrate the microscope and the streak camera to one body.
(3) The laser light incident on the specimen to generate fluorescent light is reflected from the surfaces or interfaces of lenses and the like constructing a complex optical system in the microscope, so that the specimen is re-excited by the reflected light (refer to FIG. 1) to thereby cause mismeasurement.
(4) From the same reason as described in the paragraph (3), the fluorescent light to be measured is reflected from the surfaces or interfaces of optical elements, so that the reflected fluorescent light with a little delay is overlapped onto the fluorescent light to be measured (refer to FIG. 2) to make it impossible to carry out the time resolution measurement of true fluorescence.
(5) Generally, a scale-down system is essential as an optical system for using the microscope and the streak camera in combination, so that not only the adjustment as described in the paragraphs (1) and (2) is more complicated but also the same problem as described in the paragraphs (3) and (4) exists in reflection in the scale-down system.
From the aforementioned problems, there is heretofore no existence of measuring apparatus capable of optically measuring a fine area in an object of measurement with very high spatial and time resolution.